Adjustable hollow mill.



1%. 795,167. PATENTED JULY 18, 1905. 7

H. K. PORTER. ADJUSTABLE HOLLOW MILL.

APPLICATION FILED JUL-Y 2. 1904.

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PATENTED JULY 18, 1905."

H. K. PORTER; ADJUSTABLE HOLLOW MILL.

AIPLIOATIOK FILED JULY 2, 1904.

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No. 7e5,'167.

UNITED STATES- Patented. July 18, 1905.

HENRY K. PORTER, OF CHELSEA, MASSACHUSETTS.

ADJUSTABLE HOLLOW MILL.

SPECIFICATION forming part of Letters Patent No. 795,167, dated July 18,1905, Application filed July 2. 1904. swarm. 215.044..

T (tZZ 1072,0217. zit vita-y concern.-

Be itknown that I, HENRY K. PORTER, acitizen of the United States,residing at Chelsea, in the county of Suffolk and State ofMassachusetts, have invented a new and useful Improvement in AdjustableHollow Mills, of which the following is a specification.

My invention relates to turning-tools or milling-tools of the kindusually termed hollow mills, and is an adjustable hollow mill withattachments and advantages that will be explained; and the object of myimprovement is to provide such a tool in which the cutters are readilydetachable from the head or carrier in which they are operated and areadjustable therein radially and longitudinally and so constructed andarranged as to be unusually elfective in practical use. I attain theobject stated by the construction illustrated in the accompanyingdrawings, in which Figure 1 is perspective of the tool embodying myinvention. Fig. 2 is a front view of the same in plan. Fig. 3 is a rearview. Fig.

4 is a side elevation of the body of the tool with the clamping-band andknives removed and the shank broken off. Fig. 5 is a plan of the frontface of the tool with the knives adjusted to cut a larger diameter andshowing the means and method of adjustment. Fig. 6 is a plan of thefront face of the tool with the knives removed. Fig. 7 is a centrallongitudinal section on line 7 7, Fig. 5. Fig. 8 is a perspective of oneof the knives. Fig. 9 embraces two perspectives of the adjustingshims ofunequal thickness. Fig. 10 is aperspective of an attachment to the tooltermed a chip-guard.

Referring to the drawings, in which the various parts are numbered, thesame number size required, but as illustrated is about four inches longexclusive of the shank and is hollow, being bored centrally in line withthe axis of the tool from its front face to near the shank 22. Thegrooves in which the knives are held may be cut in the sides of the bodyat an angle of about ten to fifteen degrees with a plane passing throughthe axis thereof to give the cutters when held therein the proper rake,and the cutting edges when properly adjusted longitudinally are radialto the axis of the tool. The knives are constructed from commercialquadrate bars of steel of suitable dimensions and are properly shaped ontheir outer ends 23 24 25 26 and arranged to serve as effectivecutting-blades when assembled and properly adjusted in the carrier,their interior corners 27 28 29 30 being slightly beveled to render thecutters selfcentering on the end of the stock operated upon. A pluralityof knives is most effective and any practical number may be used; but Iprefer to use four, having found that number in practical use on stockof various shapes themostdesirableandefficient. Nearlyopposite the innerend of the central hole bored in the body 13 are four clearing-holes 3132 33 34:, bored at right angles thereto through the sides 18 19 2O 21,two of which, 31 and 34:, are clearly shown in Fig. 1. The bodies of theblades cross these holes more or less, according to the angles of thegrooves, and are seen through them from the outside, but only partiallyobstruct the same without practical interference with the clearance ofthe central pocket or hollow from chips or other collections of debristhat might gather therein. Through the several sides of the band 12 arethreaded a number of clamping or binding screws, one half of whichnumber turn against the body 13, while the other half turn against theblades held in the grooves of the body. Thus the blades are held firmlyin the positions to which they are adjusted in their grooves, and theopposing screws which turn against the sides of the body counteract anytendency of those which press against the blades to distort the body.These opposing screws serve to resist the torsional strain on the bodyproduced by the blade-clamping screws when the surrounding band fitsloosely, as shown, and, as is obvious, they might be omitted if the bandwere closely fitted and fastened around the body. I prefer, however, tomake the tool substantially as shown and to use two square-headedscrews, or screws adapted to be turned with a wrench, against eachblade, as screws with slotted heads which can be tightened only with ascrew-driver do not exert sufficient pressure to hold the cutting-bladesfrom being pushed back when in use. In practice the screws with slottedheads may be what are termed plug-screws and preferably do not projectbeyond the outer faces of the clamp sides through which they are turned.Those screws which act on the blades in pairs are 35, 37, 39, and 41 andthose which oppose them, counteracting on the body in pairs, are 36, 38,40, and 42. They are shown as being part of them square-headed, whilethe remainder have less prominent slotted heads, which might better beplugscrews, as above stated. This difference in the heads has nopractical effect on the tool itself, but is thus made to somewhatcontract the tool to avoid its interference when in use with the usualcutting-off tool in the crossslide employed on the same machine, andalso to avoid contact with the finishing boxtool rest when the same isused on the screwmachine.

The cutting-blades, which are inclined to the radial planes coincidentwith their cutting edges and which project a little beyond the front ofthe hollow body, are adjustable radially in the tool by means ofmetallic shims of various thicknesses, ranging from one sixtyfourth ofan inch or less to any desired thickness. Four shims are used of eachthickness, one for each cutter; but the several thicknesses used may besuch that combinations can be made which will enable the mechanic to cuttherewith many sizes and to obtain all the nicety in degrees ofadjustment that is required. Thus with shims of one sixty-fourth, onethirty-second, three sixty-fourths, and seven sixty-fourths combinationsgiving every sixty-fourth of an inch from one sixtyfourth to thirteensixty-fourths can be made. Two of the shims, 43 and 44:, (shown inperspective in Fig. 9,) represent the form of the same. They areemployed practically in the adjustment of the cutters by placing one ormore of them of like thickness or like combination of thicknessesbetween each cutter and the bottom of the slot in which it rests, thuscarrying the blades apart radially and uniformly to the required extentto effect the reduction of the stock operated upon by this tool to thediameter required.

Another device, 49, which I term a chipguard, (shown in Fig. 10,) may beemployed. There are four of these guards, which are formed to turn thefalling chips outward or away from the central opening into the body andalso serve to protect the face of the body between the blades and theends of the adjusting-shims from abrasion by the falling chips. Theyeach comprise an adjustable slotted plate L9, adapted to be attached tothe edge of the clamp 12, and an angular branch 48, fitted to beinterposed between two adjacent blades and formed to turn away thefalling chips and to protect the face of the tool from abrasion, asdescribed.

My invention as above described constitutes an adjustable hollow millwhich by reason of its novel construction and arrangement is unusuallyeffective and rapid in its practical cutting operation, is easilyadjusted to cut stock of various shapes, either cylindrical orpolyhedral, and is comparatively cheap to construct and keep in-order.

What I claim as my invention, and desire to secure by Letters Patent, is

1. A hollow mill, comprising the combination of asquare, hollow body,terminating in a round shank; four grooves in the sides of the body;four cutting bars, or blades, fitted in the grooves; a band, or clamploosely fitted around the body and blades; a suitable number ofscrew-bolts threaded into the band to be turned against the blades, anda like number to be turned against the body; all constructed, arrangedand adapted to operate together, and relatively to each other,substantially as and for the purposes specified.

2. A hollow mill comprising the combination of a cutter-head adapted tobe attached to proper actuating mechanism, and having a centrallongitudinal opening through the same; a plurality of grooves formedlongitudinally in the exterior of the head around the central opening,and inclined to the axis of the head; a corresponding number ofcutterbars having radial cutting edges formed on the ends thereof, andfitted in said grooves so as to permit the use therewith ofmeasuringshims constructed and arranged to effect a radial adjustment ofthe bars as described; a surrounding band inclosing the bars andgrooves; and a suitable number of retainingscrews threaded through theinclosing band, and arranged to operate against the cutterbars inopposition to the shims, all as and for the purposes specified.

3. A hollow mill comprising the combination with a suitable hollow bodyprovided with a shank and constructed with recesses, of cutting-toolsfitted to said recesses, chip-guards arranged adjacent the cutting edgesformed at the ends of said'tools, means for securing the saidcutting-tools in place, and means for securing said chip-guards inplace.

HENRY K. PORTER. Witnesses:

T. K. CRAWFORD,

EUGENE HUMPHREY.

